Are HTML5 tags case sensitive ?

Last Updated : 27 Jan, 2022

In this article, we will discuss the overview of case sensitivity in HTML5. We will see the example related to it for more understanding. All the HTML elements/tags are case-insensitive. Case-insensitive means the tags/elements which are used in the code are understandable by the browser irrespective of the letters being the upper case or lower case classes.

Note: It is recommended to use all tags in lowercase or uppercase for best practice and better understanding.

Example 1: This example contains all the tags in lowercase.

HTML

<!DOCTYPE html> 
<html> 
<body> 
    <h2>Welcome To GFG</h2> 
    <p>Geeks for Geeks</p> 
    <p>The code has lowercase body tags</p> 
</body> 
</html> 

Output:

Example 2: This example contains some tags with both uppercase and lowercase alphabets. This example has <boDY> tag which has a combination of both upper and lowercase alphabets, but still, it does not affect the output.

HTML

<!DOCTYPE html> 
<html> 
  
<boDy> 
    <h2>Welcome To GFG</h2> 
    <p>Geeks for Geeks</p> 
    <p>The code has both upper and lowercase tags.</p> 
</boDy> 
</html> 

Output:

Note: You can see that both the above code snippets generate the same output.

Example 3: We used multiple tags in mixed case but we have still reached to the desired output. Tags used in mixed case in the below example are <HEAd>, </TitLe>, </heAd>, <BoDy>, , , , , and </HTmL>.

HTML

<!DOCTYPE html> 
<HTML> 
    <HEAd> 
        <Title>Welcome to GFG</TitLe> 
    </heAd> 
    <BoDy> 
        <StrONg>Hello World!</STroNg> 
        <p> 
          This is an example of Case-insensitivity 
          in HTML </bR>Observe the output 
        </p> 
  
    </body> 
</HTmL> 